201207021735 vy0wr
explained decrypted filler
3DES(name) ECB, 26 GUIDs, seed 140
From the post to its content
As posted (encrypted)
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
- Read the ciphertext. Strip whitespace: 1,680 hex characters = 840 bytes = 105 8-byte 3DES blocks.
- Derive the key. Password =
A858DE45F56D9BC9(name). Key = MD5(password) =34a14a42e98ff96095af56604e290cae, used as a two-key 3DES key. - Decrypt. 3DES-EDE2 in ECB mode, then strip the PKCS7 padding. The plaintext is 26 GUIDs as hex (shown below).
Decrypted: GUID list
1 bea6ebd4-f422-7a33-8b62-6c078c7af239 2 334abe34-b9c5-81db-8bd8-42d260afa946 3 9b881228-dce4-54fe-8415-77dda6aa6bf3 4 ea815173-a3d3-3b04-aa1c-69d87d36e500 5 ae155669-e972-3bc0-87c7-dee2378ac513 6 67887c8c-879a-8ff0-a6c0-b8abab0e86b7 7 1e8ef975-1fd8-55a2-bf12-b78b8179d167 8 e4f6a387-ee82-63b3-bf08-3ae89a2c106b 9 cd3aa5c9-6b3f-2806-9daa-5a4283b2e30d 10 5785214b-6dc9-8fa1-8b22-6b62e00b5d07 11 ab66ccee-02ec-3fb9-b593-e7cea847cf2a 12 2a80de95-e6f2-608c-8a27-4a4ccc354c6b 13 d5b265e9-77d3-7112-a030-54631885ae01 14 df4200a8-9212-2b8e-b43f-705008fae7af 15 bb3067c8-3911-887a-8411-3ce45d04f0d1 16 c6fef278-8b3e-4804-90bb-01661d012452 17 697f16a1-be93-6a98-ab13-115617e53178 18 71d4306d-4a5a-7b7f-8ad8-9939b5c64653 19 b06ea109-6d50-4ba6-b9c9-8d15b4614c88 20 bd20a7fe-c3ed-4f61-98c1-8d8776d70eec 21 219705ec-cc5c-3f17-8ca2-9b53004270a1 22 6d25d56c-769b-1de5-baae-63ec10116b72 23 9fb69255-662d-56c5-bd50-c68c57b94e1f 24 8e68e225-bc76-831e-915a-bb9be8e60eb7 25 c787bf0c-60a2-3861-bd8a-d8a15affce0e 26 06e25e5f-b7bc-56f0-9ec8-002f64ba0447
Explanation
- Explain the mask digits. The version nibble (13th hex digit) of each GUID, read in order, gives
78533856283672846744315835. Exactly this sequence comes out ofnew Random(140).Next(9): the per-post millisecond seed of the mask generator. The other 30 hex digits of each GUID areGuid.NewGuid()output and carry no message. - Explain the count. This post is draw 0 of Run 10 (seed 38,548,093):
new Random(38548093), Next(8,64) per post. The RNG predicts N = 26; the post has N = 26 ✓. The seed is the machine's uptime in ms when the app started (boot 2012-07-02 09:51–10:51). - Conclusion. Filler. The content is fully explained by the two RNGs.